Greg, if your using worm gear clamps, you might try another type of clamp. although worm gear clamps are used in many automotive applications, they aren't the best type of clamps.
These are clamps used on fuel injection hoses other than worm drive styles:
Also the real fuel injection hose is fairly expensive, last time I bought any it was about $8 a foot, probably twice that now.
https://www.google.com/search?q=the+...hrome&ie=UTF-8
The Nissan/Datsuns are pretty notorious for leaks on the fuel rails and injector plumbing. I had a neighbor back in the 90s that had one that would leak after shutting it down, he'd get a definite fuel odor in the car, and after looking at it myself, it had leaks in the fuel rail area. Not severe, but you could see the damp areas after it was shut down for a few minutes.